1. Field of Invention
The present invention belongs to the technical field of various particle processing apparatuses including particle surface modification units, crushers, mixers, kneading machines, granulating machines, feeders, and drying machines, and particularly relates to a particle processing apparatus suitable to the fields of medical products and food products, whose disassembling frequency and cleaning frequency are high.
2. Description of Related Art
Generally, in case of processing a particulate material such as a medicine (progenitor), a particle processing apparatus had been set inside a clean room building that had been closed to prevent mixture of foreign matter, and processing work had been carried out inside the room. Recently, however, in place of such a large-scale clean room building, in order to reduce the cost of equipment and running costs, so-called clean box-integrated particle processing apparatuses have been employed which house the above-mentioned various particle processing apparatuses in clean boxes having sizes suitable to the processing purposes.
However, for integration with a clean box it is, of course, required to realize compactness of the entire apparatus, and particularly, a particulate material to be processed by this apparatus is mostly an expensive medicine (progenitor), the amount to be processed is small, and various kinds are to be processed. Therefore, the processing material is frequently changed, and assembly, disassembly, and cleaning works for the processing chamber are required for each change. There are several themes and problems to be solved such as procedure simplification as well as improvement in practicability.
A first theme relates to compactness of the entire apparatus accompanied with an improvement in shaft sealing structure. Namely, describing a conventional crusher as an example, at a distance from an outer wall composing a clean box, a particle processing chamber (crusher) is disposed inside, and a rotary shaft of a drive mechanism provided outside is made to penetrate through the outer wall and connected to a rotor that is provided inside the particle processing chamber. The particle processing chamber is only independently housed in the clean box via the rotary shaft so as to be isolated from the clean box outer wall. Therefore, when cleaning the inside of the clean box and the particle processing chamber, cleaning of the back surface side of the processing chamber is difficult, so that the area around the rotary shaft penetrating portion with respect to the outer wall portion is notched so that this notched circumferential portion becomes attachable to and detachable from the box main body outer wall via a fixture such as a bolt, and after the drive mechanism is removed from the base, the particle processing chamber is taken out from the inside of the box while it is connected to the drive mechanism and then disassembled. In cleaning work, such assembly and disassembly works are troublesome and take time.
In addition, for prevention of entering of external dust into the box through a gap at the portion of the outer wall penetrated by the rotary shaft, a simple sealing means is employed in which a cleaning gas such as an N2 gas is filled inside the box and exhausted from the gap at the penetrated portion to the outside, or in addition to this, the gap is closed by a cover.
Therefore, when crushing particles into fine particles, in the abovementioned sealing means in which a cleaning gas is only filled inside the box, the fine particles flow out together with the gas from the gap at the penetrated portion although such a problem does not occur in case of coarse crushing of particles.
Furthermore, with this structure, combined with the simple sealing means, in the arrangement structure with the clean box, the distance from the bearing to the rotor lengthens, so that a structural design involving an increase in the diameter of the rotary shaft is required, resulting in a large scale of the apparatus itself. Furthermore, in a case where the rotor is rotated at a high speed, an available bearing and oil sheet are limited. Under the circumstances, it has been desired to develop a processing apparatus that is used as a processing apparatus for processing by rotation at a comparatively low speed, and is compact and can also adapt to high speed rotation processing and fine particle processing.
On the other hand, in the case of use as a device for high speed rotation, it is necessary that the distance from the bearing to the rotor is made as short as possible to shorten the rotary shaft, the bearing is lubricated by a lubricating oil, an oil sealing means is provided to prevent the lubricating oil from entering the inside of the clean box or processing chamber, and a shaft sealing means is provided to prevent particles inside the processing chamber from entering the bearing side.
The conventional shaft sealing means employed for high speed rotation is generally called single gas sealing, which has a bearing built-in shaft sealing structure in which a shaft scaling part is laid across the processing chamber and the bearing, and the shaft sealing part is provided with a circulating path for supply and exhaust of a shaft sealing gas.
Therefore, even when the pressure inside the processing chamber increases, by adjusting the valve of the shaft sealing gas outlet, the shaft sealing gas ejection amount to the inside of the processing chamber can be adjusted, however, in a case where the oil sealing means is disposed in proximity, even if a labyrinth structure is provided to increase the flowing resistance or an oil thrower is provided at the shaft sealing part,                (1) there is a possibility that the lubricating oil enters the inside of the processing chamber,        (2) there is a possibility that particles enter the bearing, and        (3) it is not possible to detect an increase in pressure inside the processing chamber although it is possible to adjust the shaft sealing gas ejection amount to the inside of the processing chamber. In all of these cases, these conventional shaft sealing means cannot be employed as they are.        
A second theme relates to simplification of processing chamber assembly and disassembly works. Namely, in the related art, as shown in FIG. 7 and FIG. 8, an impact pulverizer is divided into a particle processing chamber 1a side and a drive mechanism 2a side based on a rear cover 101a that is an attaching structure (the figure includes up to the bearing means and coupling portion, and a motor is not shown). A stator (casing) 102a and a front cover 103a as components to be provided at the processing chamber 1a side are attached to the rear cover 101a in a laminating manner, and these cannot be disassembled.
Namely, the stator 102a is screw-fixed to the rear cover 101a from the back surface side, and the rear cover 101a and the front cover 103a are connected by a fixing means including removable joint shafts 3c pivotally attached through shaft holes made in connecting parts 3a, 3b formed at one-end sides of the covers, and the front cover 103a is horizontally rotatable around the joint shaft 3c. Furthermore, at the other ends, a tightening handle 4a provided so as to be rotatable horizontally on the rear cover 101a is engaged in a concave groove 4b formed at the front cover 103a, and when a tightening operation of the handle is carried out, the front cover 103a is pressure-contacted with the stator 102a to close the covers.
To disassemble the assembled components, first, the tightening handle 4a is loosened to release the engagement with the concave groove 4b, the joint shaft 3c is removed, and the cover 103a is removed. Then, the stator 102a attached to the rear cover 101a is removed to complete disassembly, and it becomes possible to carry out cleaning work of the respective components.
However, with this construction, since the front cover 103a and the stator 102a are attached to the rear cover 101a by separate setting means, the structure becomes complicated, and when assembly and disassembly works are carried out, a screw tightening operation while supporting the members is required, and particularly in disassembly, supporting must be continued for a long period of time until all the screws are removed, and therefore, it is difficult for one operator to carry out these works by himself/herself, and working efficiency is low. During cleaning work, due to the existence of the connecting part 3b at the front cover 103a, the existence of the connecting part 3a and the tightening handle 4a at the rear cover 101a, and the existence of the setting means, cleaning of inside holes of connecting parts 3a, 3b, corners of an attachment base, the rotating joint of the tightening handle 4a, the tightening screw portions, and the screw holes at the stator 102a is difficult and takes time, and furthermore, when the components form a multi-layered structure due to addition of a casing composing the shaft sealing part, the cleaning work takes more time. Particularly, in a case where the material to be processed is frequently changed, the assembly, disassembly, and cleaning work frequencies inevitably increase, and this lowers the productive efficiency, and causes defective cleaning.
When a particulate material such as a medicine (progenitor) is processed, a so-called clean box-integrated particle processing apparatus in which a particle processing chamber is housed in a clean box that is sealed so as to prevent entering of foreign matter is used, however, in this case, working efficiency further lowers.
A third theme relates to the processed states and the raw material supplying means. Namely, although the amount to be processed at a time in the processing chamber depends on the physical properties of the raw material to be processed, supply of a quantitatively-controlled amount is desirable to generate ground particles without unevenness in particle size.
Conventionally, the front surface side of the box outer wall is constructed as an operating part, and an operator inserts his/her hands into right and left arm gloves for maintenance provided at the operating part, and manually supplies a raw material to a raw material hopper by using a quantitatively-controlled amount cup, whereby raw material supply to the processing apparatus installed inside a clean box is carried out.
However, in a production process requiring continuous supply of the same kind of raw material, it is very difficult for such a manual supply to cope with continuous supply since such a manual supply not only lowers the working efficiency but also requires a high-level of skill for a uniform supply over a long period of time. Accordingly, an automatic supply unit for supplying a quantitatively-controlled amount of material is proposed, however, in the special environment inside a clean box, it is necessary to select which should be used, manual supply or supply by the automatic supply unit balancing between short-time supply and long-time supply, and in addition, sealing performance inside and outside the box and workability in assembly and disassembly accompanied with cleaning work must be taken into consideration, and it has been demanded to develop a quantitatively-controlled amount supply unit that is suitable to special usage of a clean box.